1273 


Issued  June  30, 1910. 

U.  S.  DEPARTMENT  OF  AGRICULTURE. 


FARMERS’  BULLETIN  404 


IRRIGATION  OF  ORCHARDS. 


BY 

SAMUEL  FORTIER, 

Chief  of  Irrigation  Investigations , 
Office  of  Experiment  Stations. 


WASHINGTON: 

GOVERNMENT  PRINTING  OFFICE. 

1910. 


LETTER  OF  TRANSMITTAL. 


U.  S.  Department  of  Agriculture, 

Office  of  Experiment  Stations, 
Washington ,  D.  O.,  Aril  25,  1910. 

Sir:  I  have  the  honor  to  transmit  herewith  material  for  a  bulletin 
on  the  irrigation  of  orchards,  prepared  by  Samuel  Fortier,  chief  of 
irrigation  investigations  of  this  Office.  This  material  is  based  on 
the  best  irrigation  practices  of  the  arid  region,  and  is  intended  pri¬ 
marily  for  the  use  of  settlers  in  that  region.  It  is  therefore  recom¬ 
mended  that  it  be  published  as  a  Farmers’  Bulletin. 

Doctor  Fortier  desires  to  acknowledge  the  receipt  of  notes  on  the 
irrigation  of  orchards  from  state  agents  of  this  Office  and  special 
agents  appointed  temporarily  for  this  and  other  purposes. 

Respectfully, 


A.  C.  True, 

Director. 


Hon.  James  Wilson, 

Secretary  of  Agriculture. 


404 

2 


6 


C  0  N  T  E  NTS. 


Tage. 

Selection  of  lands  for  orchards .  5 

Typical  water  supplies  for  orchards .  6 

Clearing  and  grading  land  for  fruit .  9 

Locating  the  tree  rows .  10 

Methods  of  irrigating  orchards .  12 

Furrow  irrigation .  12 

Earthen  head  ditches.  . .  13 

Short  tubes  in  head  ditches .  14 

Head  flumes .  15 

Pipes  and  standpipes .  17 

Making  furrows .  19 

Applying  water  to  furrows .  20 

The  basin  method .  22 

The  check  method .  23 

Time  to  irrigate  orchards .  24 

Number  of  irrigations  per  season .  25 

Duty  of  water  in  orchard  irrigation . 25 

Evaporation  losses  from  orchard  soils .  2< 

Effect  of  soil  mulches  in  checking  evaporation . 

Loss  of  wTater  due  to  percolation . 

Removal  of  waste  water .  . 

Growing  crops  between  the  tree  . .  ^ 

Winter  irrigation  of  orchards . 

404 

*> 

O 


ILLUSTRATIONS. 


Page. 

Fig.  1.  Orchard  tracts  at  Lewiston,  Idaho .  6 

2.  Weir,  with  automatic  register,  used  by  the  Temescal  Water  Company.  7 

3.  Concrete-lined  canal  of  the  Temescal  Water  Company .  7 

4.  Section  of  hydrant  box  of  Riverside  Water  Company,  showing  device 

for  measuring  miner’s  inches .  8 

5.  Orchard  tract  under  Gage  Canal,  Riverside,  Cal .  8 

6.  Hexagonal  method  of  setting  out  orchard  trees .  11 

7.  Plan  of  planting  apple  trees  with  peach  trees  as  fillers .  12 

8.  The  use  of  the  “A”  scraper  in  building  head  ditches .  13 

9.  Wooden  box  placed  in  bank  of  head  ditch .  14 

10.  Wooden  check  in  head  ditch .  15 

11.  Section  of  wooden  head  flume,  showing  opening  and  gate .  15 

12.  The  use  of  low  check  in  head  flume . . .  16 

13.  Common  sizes  of  concrete  head  flumes .  17 

14.  Earthen  head  ditch  lined  with  concrete .  ,  17 

15.  The  use  of  pipes  in  furrow  irrigation .  18 

16.  Section  of  standpipe  outlined  in  figure  15 .  18 

17.  Method  of  irrigating  from  iron  standpipes  connected  with  pressure 

pipes . •  19 

18.  Making  furrows  in  orchard .  20 

19.  Furrow  irrigation,  showing  dry  spaces .  21 

20.  Cross  furrowing  the  dry  spaces .  21 

21.  Use  of  zigzag  furrows .  22 

22.  Basin  method  of  irrigation .  23 

23.  Ridger  used  in  basin  irrigation .  23 

24.  Combination  of  check  and  furrow  methods .  23 

25.  Average  duty  per  month  under  Riverside  Water  Company,  December 

1,  1901,  to  November  30,  1908  .  26 

26.  Relation  between  temperature  and  evaporation  from  a  water  surface 

at  Tulare,  Cal .  28 

27.  Tank  experiments  at  Reno,  Nev.,  to  determine  effect  of  soil  mulches 

in  checking  evaporation .  30 

28.  Outlines  of  percolation  under  sixteen  furrows  in  orchard  58  under  the 

Gage  Canal  Company,  Riverside,  Cal .  31 

29.  Soil  auger  used  to  locate  ground-water  level . _ .  32 

30.  Box  drain .  32 

31.  Sand  box  in  tile  line .  33 

32.  Orchard,  showing  strawberries  between  rows  of  trees .  35 

404 


4 


IRRIGATION  OF  ORCHARDS. 


SELECTION  OF  LANDS  FOE  OECHAEDS. 


Care  and  good  judgment  should  be  exercised  in  the  selection  of  an 
orchard  tract.  If  it  turns  out  well  the  profits  are  high,  but  if  it  fails 
the  losses  are  heavy.  It  involves  the  setting  aside  of  good  land,  the 
use  of  irrigation  water,  and  somewhat  heavy  expenses  in  purchasing 
trees,  setting  them  out  and  caring  for  them  until  they  begin  to  bear. 

Assuming  that  the  climate  and  soil  of  the  district  selected  are 
adapted  to  the  kind  of  trees  to  be  grown,  the  next  most  important 
things  to  consider  are  good  drainage  and  freedom  from  early  and  late 
frosts.  Low-lying  lands  under  a  new  irrigation  system  should  be 
regarded  with  suspicion,  even  if  the  subsoil  be  quite  dry  at  the  time  of 
planting.  The  results  of  a  few  years  of  heavy  and  careless  irrigation 
on  the  higher  lands  adjacent  may  render  the  lowlands  unfit  for  or¬ 
chards.  On  the  other  hand,  the  higher  lands  are  not  always  well 
drained  naturally.  A  bank  of  clay  extending  across  a  slope  may  inter¬ 
cept  percolating  water  and  raise  it  near  the  surface.  Favored  locations 
for  orchards  in  the  mountain  States  are  often  found  in  the  narrow 
river  valleys  at  the  mouths  of  canyons.  The  coarse  soil  of  these  deltas, 
the  steep  slopes,  and  the  daily  occurrence  of  winds  which  blow  first 
out  of  the  canyons  and  then  back  into  them,  afford  excellent  conditions 
for  the  production  of  highly  flavored  fruits  at  the  minimum  risk  of 
being  injured  by  frost. 

Proper  exposure  is  another  important  factor.  In  the  warmer  re¬ 
gions  of  the  West  and  Southwest  a  northern  exposure  is  sometimes 
best,  but  as  a  rule  the  orchards  of  the  West  require  warmth  and  sun¬ 
shine,  and  a  southerly  exposure  is  usually  most  desirable.  Natural 
barriers  frequently  intercept  the  sweep  of  cold,  destructive  winds,  and 
when  these  are  lacking,  wind-breaks  may  be  planted  to  serve  the  same 
purpose.  Depressions  or  sheltered  coves  should  be  avoided  if  the  cold 
air  has  a  tendency  to  collect  in  them,  a  free  circulation  of  air  being 
necessary  to  drive  away  frost.  The  low-lying  lands  seem  to  be  the 

most  subject  to  cold,  stagnant  air. 

While  experience  has  shown  that  orchard  trees  ot  nearly  all  kind* 
can  be  successfully  grown  on  soils  that  differ  widely  in  their  mechan¬ 
ical  and  chemical  composition,  it  has  also  shown  that  certain  t\pi* 
of  soils  are  best  adapted  to  particular  kinds  of  trees.  1  hus  the  be st 

404 


5 


6 


IRRIGATION  OF  ORCHARDS. 


peach,  almond,  apricot,  and  olive  orchards  of  the  West  are  found  on 
the  lighter  or  sandier  loams;  the  best  apple,  cherry,  and  pear  orchards 
on  heavier  loams;  while  walnut,  prune,  and  orange  orchards  do  best 
on  medium  grades  of  soil.  The  requirements  of  all,  however,  are  a 
deep  rich,  and  well-drained  soil. 

TYPICAL  WATER  SUPPLIES  FOR  ORCHARDS. 

Formerly  most  western  orchards  were  supplied  with  water  through 
earthen  ditches.  These  leaky,  unsightly  channels,  by  reason  of  their 

J  1 _ 1  L 


BRYDEN  AVE. 


n  i — ; - — - 1  r 

Fig.  1. — Orchard  tracts  at  Lewiston,  Idaho. 


cheapness,  would  have  been  quite  generally  retained  had  it  not  been 
for  the  increasing  value  and  scarcity  of  water.  The  value  of  wTater 
for  irrigation  purposes  has  increased  beyond  the  average  of  that 
given  by  the  census  report  of  1902  over  300  per  cent.  In  many  locali¬ 
ties  there  is  likewise  great  scarcity  at  certain  times.  These  rapidly 
changing  conditions  have  induced  many  water  companies  to  save 

404 


IRRIGATION  OF  ORCHARDS. 


7 


®Wfe. 

*$gp1°r  *\  *  At 
' '/ 


^isddt&d-'d. 


some  of  their  heavy  losses  in  conveying  water  supplies  by  substituting 
pipes  for  open  ditches  in  earth,  or  else  by  making  the  ditches  water¬ 
tight  by  an  impervious  lining. 

The  high  value  and  scarcity  of  the  water  in  natural  streams  have, 
likewise  induced  orchardists  to  install  pumping  plants  to  raise  water 
from  underground 
sources.  It  was  esti¬ 
mated  that  in  1909 
20,000  of  these  plants 
were  in  operation  in 
California  alone.  In 
other  parts  of  the 
West  reservoirs  are 
being  built  to  supple¬ 
ment  the  late  summer 
flow  of  streams  which 
fail  to  provide  enough 
water  for  all. 

The  few  typical  ex¬ 
amples  which  follow 
may  not  only  give  the 
reader  an  idea  of  how 
orchards  are  supplied  with  water,  but  indicate  also  the  customary 
division  into  tracts  to  serve  this  and  other  purposes. 

The  Lewiston  Basin  is  located  where  Clearwater  River  flows  into 
the  Snake  River  in  western  Idaho,  and  varies  from  700  to  1,900  feet 
above  sea  level.  A  few  years  ago  water  was  brought  from  neighbor¬ 
ing  creeks  and  stored  in  a  reservoir.  The  water  required  for  orchard 

irrigation  is  conducted 
from  this  reservoir 
under  pressure  in  two 
lines  of  redwood  stave 
pipes  over  the  rolling 
hills  which  separate 
the  reservoir  from  the 
orchard  lands.  On 
these  lands  contour 
lines  were  first  estab¬ 
lished,  and  each  quarter  section  was  afterwards  divided  into  10-acie 
tracts  by  60-foot  streets.  These  were  further  subdivided  into  eight 
5-acre  tracts,  with  a  20-foot  alley  through  the  center.  ligme  1, 
showing  block  28  of  the  survey,  indicates  the  general  arrangement. 
The  large  conduits  from  the  reservoir  are  connected  to  smaller  lateral 


Fig.  2. — Weir  with  automatic  register,  used  by  the 
Temescal  Water  Company. 


fo/ned  p/dsfer.  : 

2'/z  /ned  concrete  *  {55 


'/otned p/os ter 
2'/i/ncti  concrete 


•'  -.V:  •  3  /o'd  fnc/>  concrete' •:  ' 

Fig.  3. — Concrete-lined  canal  of  the  Temescal  Water 

Company. 


404 


8 


IRRIGATION  OF  ORCHARDS. 


pipes  laid  in  the  alleys,  and  these  in  turn  are  tapped  by  3-inch  pipes, 
which  furnish  water  to  the  5-acre  tracts. 

The  town  of  Corona,  Cal.,  is  hemmed  in  on  all  sides  by  lemon  and 
orange  orchards.  The  chief  water  supply  for  these  groves  comes  from 
Perris  Basin,  40  miles  distant.  The  Temescal  Water  Company  owns 


Fig.  4. — Section  of  hydrant  box  of  Riverside  Water  Com¬ 
pany,  showing  device  for  measuring  miner’s  inches. 


3, GOO  acres  of  water¬ 
bearing  lands  in  this 
basin,  and  at  favor¬ 
able  points  pumping 
plants  have  been  in¬ 
stalled.  These  plants 
are  operated  by  mo¬ 
tors  supplied  with 
current  from  a  central 
generating  station  lo¬ 


cated  at  Ethenac.  The  discharge  from  each  pump  is  measured  over  a 
rectangular  wier  having  an  automatic  register.  This  device  is  shown 
in  figure  2.  Small  lined  channels  convey  the  water  from  the  pumps 
to  the  main  conduit  shown  in  cross-section  in  figure  3.  The  con¬ 
crete  lining  of  this 
conduit  is  composed 
of  one  part  cement 
to  seven  parts  sand 
and  gravel,  having 


a 

slop( 


r/rrigotino  Flume 


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9Z8.0C 

Irrigating  Flume 

- 

92  5.  50 

J 

thickness  on  the 
>es  of  2^  inches 
and  on  the  bottom 
of  3  to  4  inches. 

The  lining  is  ren¬ 
dered  still  more  im¬ 
pervious  by  the  ad¬ 
dition  of  a  plaster 
coat  one-fourth  of 
an  inch  in  thick¬ 
ness,  composed  of 
one  part  of  cement 
to  two  parts  of 
sand.  The  cost  was 
5J  cents  per  square 
foot,  or  55  cents  per 
linear  foot.  The  main  conduit  consists  of  about  30  miles  of  lined 
canal  and  10  miles  of  piping  30  inches  in  diameter.  The  groves  are 
laid  out  as  a  rule  in  10-acre  tracts,  and  piping  of  various  kinds  con¬ 
veys  the  water  from  the  main  to  the  highest  point  of  each  tract,  from 
which  it  is  distributed  between  the  rows  in  furrows. 


LINCOLN  AVENUE 


926.40 


305.40 


f Hydrant 


926.90 


929.90 


Fig. 


-Orchard  tract  under  Gage  Canal,  Riverside,  Cal. 


404 


IRRIGATION  OF  ORCHARDS. 


9 


A  large  part  of  the  water  used  by  the  Riverside  Water  Company 
is  pumped  from  the  gravelly  bed  of  the  Santa  Ana  River.  From 
thence  it  is  conveyed  in  a  main  canal  to  the  orchard  lands  and  dis¬ 
tributed  to  the  groves  in  cement  and  vitrified  clay  pipes.  The  owner 
of  a  tract,  whether  it  be  10,  20,  30,  or  40  acres  in  extent,  receives  his 
supply  at  the  highest  corner  through  a  hydrant  box.  Each  hydrant 
box  not  only  allows  the  water  to  pass  from  the  end  of  a  lateral  pipe 
to  the  head  flume  of  the  tract  to  be  irrigated,  but  also  measures  the 
amount  in  miner’s  inches  under  a  4-inch  pressure  head  as  it  passes 
through.  A  section  of  the  hydrant  box  showing  the  adjustable  steel 
slides  to  regulate  the  opening  is  given  in  figure  4. 

On  the  Gage  Canal  system  in  Riverside  County,  Cal.,  the  water 
supply  for  the  tiers  of  40-acre  tracts  is  taken  from  the  canal  in  riveted 
steel  pipes  varying  from  6  to  10  inches  in  diameter.  These  larger 
mains  are  connected  with  4,  5,  and  6  inch  lateral  pipes  of  the  same 
material,  which  convey  the  water  to  the  highest  point  of  each  10-acre 
tract.  This  general  arrangement  is  shown  in  the  sketch,  figure  5. 

The  ditches  conducting  water  from  gravity  canals  to  orchard  tracts 
do  not  differ  from  the  supply  ditches  for  other  crops  which  have 
been  described  in  previous  publications  of  this  Department.® 


CLEARING  AND  GRADING  LAND  FOR  FRUIT. 

As  a  rule  fruit  trees  are  planted  on  land  previously  cultivated  and 
cropped.  One  of  the  best  preparatory  crops  for  orchards  is  alfalfa. 
This  vigorous  plant  breaks  up  the  soil  and  subsoil  by  its  roots,  collects 
and  stores  valuable  plant  foods,  and  when  it  is  turned  under  at  the 
end  of  the  second  or  third  year  leaves  the  soil  in  much  better  condi¬ 
tion  for  the  retention  of  moisture  and  the  growth  of  young  trees. 

In  the  Bitter  Root  Valley,  Montana,  new  land  is  first  plowed  8  to  12 
inches  deep,  then  carefully  graded  and  smoothed  and  seeded  to  red 
clover  for  one  or  two  seasons.  On  the  west  side  of  this  valley  pine 
trees  and  pine  stumps  are  encountered.  These  can  best  be  removed 
by  burning.  A  hole  1^  inches  in  diameter  is  bored  through  the  base 
of  the  stump  or  tree  in  a  slanting  direction.  It  is  near  the  surface 
of  the  ground  on  the  windward  side  and  about  18  inches  above  the 
surface  on  the  leeward  side.  A  fire  is  then  built  in  the  hole,  using 
small  twigs  to  start  it.  As  the  fire  burns  the  opening  is  increased 
and  larger  limbs  are  inserted.  In  two  or  three  days  the  stump  v>\\\ 
have  burned  out,  the  fire  burning  down  into  the  roots  to  a  depth  of 
12  to  14  inches.  The  cost  of  such  clearing  varies  with  the  charactei 
of  the  land  and  the  density  of  the  growth.  From  $10  to  $b>  an  acie 
will  clear  the  land  of  stumps  and  it  then  costs  $5  to  $10  to  get  the 
unburnt  roots  plowed  out  and  the  land  ready  for  planting. _ 

a  u.  S.  Dept.  Agr.,  Farmers’  Bills.  263  and  373, 

41647— Bull.  404—10 - 2 


10 


IRRIGATION  OF  ORCHARDS. 


Iii  recent  years  lar^e  areas  of  wooded  lands  in  both  the  Hood  River 

%j  o 

and  Rogue  River  valleys  of  Oregon  have  been  cleared  in  order  to 
plant  apple  trees.  One  of  the  methods  employed  in  the  Hood  River 
district  to  rid  the  land  of  its  growth  of  fir,  pine,  scrub  oak,  and  laurel 
is  similar  to  that  just  described.  Another  method  consists  in  split¬ 
ting  open  the  stumps  with  giant  powder  and  then  pulling  out  the 
roots  with  a  stump  puller.  Stump  pullers  of  various  kinds  are  used 
in  California  for  a  like  purpose.  The  most  powerful  of  these  con¬ 
sists  of  a  portable  engine,  windlass,  and  cable  similar  to  an  ordinary 
hoisting  plant.  A  heavy  chain  is  fastened  to  the  tree  at  the  proper 
height  above  the  ground.  To  this  chain  the  pulling  cable  is  hooked 
and  when  the  power  is  applied  the  tree  is  pulled  out  by  the  roots. 

In  New  Mexico  and  Texas  the  mesquite  is  usually  grubbed  out  by 
Mexicans,  but  in  California,  where  labor  costs  more,  such  shrubs  as 
mesquite,  manzanita,  and  chaparral  can  be  more  cheaply  removed  by 
a  stout  pair  of  horses  and  a  logging  chain. 

Devices  for  the  removal  of  ordinary  desert  plants,  such  as  sage¬ 
brush  and  grease  wood  have  been  described  in  a  previous  bulletin.0 

An  effort  should  be  made  to  establish  a  fairly  uniform  grade  from 
top  to  bottom  of  each  tract.  This  is  done  by  cutting  off  the  high 
points  and  depositing  the  earth  thus  obtained  in  the  depressions. 
The  length  of  the  furrows  should  not  exceed  one-eighth  of  a  mile 
and  in  sandy  soil  they  should  be  shorter.  As  a  rule,  it  is  not  difficult 
to  grade  the  surface  of  an  orchard  so  that  small  streams  of  water 
will  readily  flow  in  furrows  from  top  to  bottom. 

LOCATING  THE  TREE  ROWS. 

In  setting  out  orchards  which  are  to  be  irrigated,  the  elevation  of 
the  surface  of  the  ground  should  first  be  ascertained?  This  is  usually 
done  by  making  a  contour  survey  by  which  each  tract  is  divided  up 
into  a  number  of  curved  strips  or  belts  by  level  lines.  Such  contours 
are  shown  in  figure  1,  page  G,  the  vertical  distance  between  them  in 
this  particular  case  being  1  foot.  With  these  as  a  guide  the  direction 
of  the  tree  rows  can  be  readily  determined.  Where  the  trees  are 
watered  in  basins  or  checks,  flat  slopes  are  not  so  objectionable,  but  in 
furrow  irrigation  a  slope  of  about  2  inches  to  the  100  feet  is  necessary 
to  insure  an  even  distribution  of  water.  When  streams  are  to  be  run 
in  the  furrows  the  slope  of  the  furrows  may  be  increased  to  8,  10,  and 
even  to  12  inches  to  the  100  feet.  On  slopes  varying  from  10  to  40 
feet  to  the  mile,  the  tree  rows  may  therefore  be  located  at  the  proper 
distance  apart  down  the  steepest  slope.  Under  such  conditions  the 
trees  are  most  commonly  planted  in  squares.  The  location  of  the 


404 


a  U.  S.  Dept.  Agr.,  Farmers’  Bill.  373. 


IRRIGATION  OF  ORCHARDS. 


11 


trees  can  be  best  fixed  by  the  use  of  a  surveyor’s  transit  and  steel  tape 
When  these  are  not  available,  a  woven- wire  cable  about  three-six¬ 
teenths  of  an  inch  in  diameter  will  answer  the  purpose.  If  apple 
trees  are  to  be  set  out  and  it  is  desired  to  have  them  32  feet  apart 
tags  are  inserted  between  the  strands  of  the  cable  to  mark  this  exact 
distance.  A  base  line  at  the  proper  distance  from  the  fence  or  one 
margin  of  the  field  is  then  laid  down  and  long  sighting  stakes  driven 
at  each  tag.  The  corner  is  then  turned  and  a  similar  line  is  laid  out. 
This  process  is  continued  until  the  location  of  the  trees  around  each 
of  the  four  sides  of  the  tract  has  been  fixed.  The  corners  can  be^t 
be  turned  with  a  100-foot  tape  or  link  chain.  First  measure  from 
the  end  of  the  base  line  a  distance  of  30  feet.  Hold  the  one-hundred 
end  of  the  chain  at  this  point,  and  the  10-foot  link  at  the  corner;  take 
the  tape  or  chain  at  the  50-foot  mark  or  link  and  pull  both  lines  taut. 


A  stake  driven  at  this  vertex  will  establish  a  point  on  a  line  at  right 
angles  to  the  first.  When 
stakes  have  been  set  on  all 
four  sides  the  intermediate 
locations  for  the  trees  can 
be  readily  ascertained  by 
sighting  between  corre- 


Fig.  6. 


-Hexagonal  method  of  setting  out  orchard 
trees. 


sponding  marginal  stakes. 

Where  the  slope  is  steep 
and  difficulties  are  likely  to 
be  encountered  in  distribut¬ 
ing  water,  the  equilateral, 
hexagonal,  or  septuple 
method  of  planting,  as  it 
is  variously  termed,  should 
be  adopted.  The  manner  of  marking  the  ground  for  this  method  is 
indicated  in  figure  6.  It  will  be  observed  that  in  this  method  the 
ground  is  divided  up  into  equilateral  triangles,  with  a  tree  at  each 
vertex.  The  trees  likewise  form  hexagons,  and  when  one  includes 
the  center  tree  of  each  hexagon  they  form  groups  of  sevens.  Hence 
the  name  equilateral,  hexagonal,  and  septuple. 

The  chief  advantage  of  this  mode  of  planting  in  irrigated  districts 
is  that  it  provides  three  and  often  four  different  directions  in  which 
furrows  may  be  run.  Having  the  choice  of  so  many,  it  is  not  diffi¬ 
cult  to  select  the  one  which  is  best  for  any  particular  tract.  1  he 
ground  can  likewise  be  cultivated  in  more  ways,  and  about  one- 
seventh  more  trees  can  be  planted  to  a  given  area  than  is  possible  in 
the  square  method. 

In  the  past  the  trees  of  irrigated  orchards  have  been  planted  too 
close.  This  is  made  clear  to  even  the  casual  observer  who  visits  the 


404 


12 


IRRIGATION  OF  ORCHARDS. 


old  orange  groves  of  Riverside,  Cal.,  the  deciduous  orchards  of  the  * 
Santa  Clara  Valley,  California,  or  the  apple  orchards  of  the  Hood 
River  district  in  Oregon.  Under  irrigation  systems  peach  trees 
should  be  spaced  20  to  22  feet,  olive,  pear,  apricot,  and  cherry  trees 
from  22  to  28  and  30  feet,  orange  trees  22  to  24  feet,  apple  trees  30 
to  3G  feet,  and  walnut  trees  from  48  to  5G  feet  apart. 

On  the  Pacific  coast  the  tendency  toward  wide  spacing  has  induced 
many  growers  to  insert  peach  fillers  between  other  slower  maturing 
trees,  such  as  the  apple  and  walnut.  A  common  practice  in  this 
direction  is  shown  in  figure  7,-  which  represents  the  arrangement 
of  trees  in  a  young  orchard  in  Douglas  County,  Wash.  Here  the 
trees  are  set  in  squares  18  feet  each  way,  but  in  every  other  row  peach 
trees  alternate  with  the  standard  apple  trees.  In  the  remaining  rows 
winesap  apple  trees  are  used  for  fillers.  As  the  apple  trees  grow  and 
begin  to  crowd  the  fillers,  the  peach  trees  are  removed.  If  more 


Spitz  Peach  Spitz 


iff - * - /S' 


iff 


id' 


Jonathan 


Ffeach 


a 


Jonathan 


A. 


Spitz 


Jonathan 


Winesap 


Jonathan 


B. 


Spitz  Spitz 


a 


Jonathan 


Fig.  7. — Plan  of  planting  apple  trees  with  peach  trees  as  fillers  :  A,  Trees  as  planted  at 

first ;  B,  peach  trees  removed  ;  C.  Winesap  removed. 


space  is  required  the  winesaps  can  be  taken  out,  leaving  the  apple 
trees  in  squares  36  feet  apart  both  ways. 

METHODS  OF  IRRIGATING  ORCHARDS. 

FURROW  IRRIGATION. 

The  usual  way  of  irrigating  orchards  is  by  means  of  furrows. 
These  vary  in  depth,  length,  and  distance  apart,  but  this  diversity 
does  not  tend  to  create  different  kinds  of  furrow  irrigation.  The 
division  of  this  subject  is  rather  due  to  the  means  employed  in  dis¬ 
tributing  water  from  the  supply  ditch  to  the  furrows.  In  some 
cases  the  distribution  is  effected  by  making  openings  in  an  earthen 
ditch,  in  others  by  inserting  wooden  or  iron  spouts  in  the  ditch  banks, 
while  in  many  others  flumes  having  the  desired  number  of  openings 
or  pipes  with  standpipes  divide  the  supply  among  the  requisite  num¬ 
ber  of  furrows.  These  designs  and  methods  will  be  described  under 
their  respective  headings. 

404 


IRRIGATION  OF  ORCHARDS. 
Earthen  Head  Ditches. 


13 


Permanent  ditches  at  the  head  of  orchard  tracts  should  be  located 
by  a  surveyor.  The  proper  grade  depends  chiefly  on  the  soil.  If 
the  soil  is  loose  and  easily  eroded,  a  slow  velocity  is  best.  On  the 
other  hand,  the  velocity  must  be  sufficiently  rapid  to  prevent  the 
deposition  of  silt  and  the  growth  of  water  plants.  In  ordinary  soils, 
a  grade  of  2^  inches  to  100  feet  for  a  ditch  carrying  2  cubic  feet 
per  second  is  not  far  out  of  the  way.  The  amount  of  water  to  be 
carried  varies  from  J  to  2  or  more  cubic  feet  per  second.  A 
ditch  having  a  bottom  width  of  24  inches,  a  depth  of  G  inches,  and 
sloping  sides,  ought  to  carry  1^  cubic  feet  per  second  on  a  grade  of 


Fig.  8. — The  use  of  the  “A”  scraper  in  building  head  ditches. 

half  an  inch  to  the  rod  or  3  inches  to  100  feet.  Such  a  ditch  may 
be  built  by  first  plowing  four  furrows  and  then  removing  the  loose 
earth  either  with  shovels  or  a  narrow  scraper.  The  loose  earth  may 
likewise  be  thrown  up  on  the  sides  and  top  b}^  means  of  the  home¬ 
made  implement  shown  in  figure  8.  Canvas  dams,  metal  tappoons, 
or  other  similar  devices  are  inserted  in  the  head  ditch  to  raise  the 
surface  of  the  water  opposite  that  part  of  the  orchard  where  furrows 
have  been  made  and  which  is  about  to  be  watered.  The  chief  diffi¬ 
culty  in  this  mode  of  furrow  irrigation  arises  in  withdrawing  water 
from  the  ditch  and  in  distributing  it  equally  among  a  large  number 
of  furrows.  A  skilled  irrigator  may  adjust  the  size  and  depth  of 
the  ditch  bank  openings  so  as  to  secure  a  somewhat  uniform  flow  in 
the  furrows,  but  constant  attention  is  required  in  order  to  maintain  it. 

404 


14 


IRRIGATION  OF  ORCHARDS. 


If  the  water  is  permitted  to  flow  for  a  short  time  unattended  the  dis¬ 
tribution  is  likely  to  become  unequal.  Parts  of  the  ditch  bank 
become  soft,  and,  as  the  water  rushes  through,  the  earth  is  washed 
away,  permitting  larger  discharges  and  lowering  the  general  level 
of  the  water  in  the  ditch  so  that  other  openings  may  have  no  dis¬ 
charge.  Some  of  the  orchardists  of  San  Diego  County,  Cal.,  insert  in 
niches  cut  in  the  bank  pieces  of  old  grain  sacks  or  tent  cloth.  The 
water  flows  over  these  without  eroding  the  earth.  Another  device  is 
to  use  a  board  pointed  at  the  lower  end  and  containing  a  narrow 
opening  or  slot  through  which  the  water  passes  to  the  furrow.  Shin¬ 
gles  are  also  used  to  regulate  the  flow  in  the  furrows.  The  thin  ends 
of  these  are  stuck  into  the  ground  at  the  heads  of  furrows. 


Short  Tubes  in  Head  Ditches. 


In  recent  years  short  tubes  or  spouts  have  been  used  in  many  of 
the  head  ditches  of  orchards  to  divert  small  quantities  of  water  to 

furrows.  These  tubes  are  usually 
made  of  wood,  but  pipes  made  of 
clay,  black  iron,  galvanized  iron, 
and  tin  are  occasionally  used. 

For  nurseries  and  young  trees 
especially,  and  also  for  mature 
trees,  a  cheap  and  serviceable 
tube  may  be  made  from  pine 
lath,  such  as  are  used  for  plaster- 
The  4- foot  lengths  are  cut 


Fig. 


9. — Wooden  box  placed  in  bank  of 
head  ditch. 


mg. 


into  two  equal  parts  and  four  of 
these  pieces  are  nailed  together  to  form  a  tube.  One  of  these  tubes 
when  placed  with  its  center  2  inches  below  the  surface  of  the  water 
in  the  head  ditch  discharges  nearly  three-quarters  of  a  miner’s  inch 
of  water,  and  if  placed  4  inches  below  the  surface  will  discharge 
more  than  1  miner’s  inch.  In  southern  Idaho  the  lumber  mills  manu¬ 
facture  a  special  lath  for  this  purpose.  It  is  4  inch  thick,  2  inches 
wide,  and  36  inches  long.  If  such  tubes  when  thoroughly  dry  are 
dipped  in  hot  asphalt  they  will  last  a  much  longer  time.  In  some 
of  the  deciduous  orchards  of  California  a  still  larger  wooden  tube 
or  box  is  used.  Figure  9  represents  one  of  these.  It  is  made  of  four 
pieces  of  J  by  3J  inch  redwood  boards  of  the  desired  length.  The 
flow  through  this  tube  is  regulated  by  a  cheap  gate,  consisting  of  a 
piece  of  galvanized  iron  fastened  by  means  of  a  leather  washer  and 
a  wire  nail. 

The  orchardist  who  lives  near  a  manufacturing  town  or  citv  can 

O  r- 

often  purchase  at  a  low  figure  pieces  of  worn-out  and  discarded 
piping  varying  from  f  to  2  inches  in  diameter.  Such  pipes  when 

404 


IRRIGATION  OF  ORCHARDS. 


15 


cut  into  suitable  lengths  make  a  good  substitute  for  wooden  spouts. 
Tin  tubes  one-half  inch  in  diameter  and  of  the  proper  length  have 
been  used  with  good  success.  In  compact  soils,  through  which  water 
passes  very  slowly, 
the  furrows  must  be 
near  together,  and 
under  such  condi¬ 
tions  small  tin  tubes 
are  to  be  preferred. 

In  making  use  of 
tubes  of  various 
kinds  to  distribute 
water  to  furrows  it 
is  necessary  to  main¬ 
tain  a  constant  head 
in  the  supply  ditch. 

This  is  done  by  in¬ 
serting  checks  at 
regular  distances. 

These  distances  vary 
with  the  grade  of 
the  ditch,  but  150  feet  is  not  far  from  being  an  average  spacing. 
In  temporary  ditches  the  canvas  dam  is  perhaps  the  best  check,  but 
in  permanent  ditches  it  pays  to  use  wood  or  concrete.  An  effective 
wooden  check  is  shown  in  figure  10.  In  this  the  opening  is  con¬ 
trolled  by  a  dashboard 
which  may  be  adjusted  so 
as  to  hold  the  water  at 
any  desired  height  and 
at  the  same  time  permit 
the  surplus  to  flow  over 
the  top  to  feed  the  next 
lower  set  of  furrows. 

Head  Flumes. 
Formerly  head  flumes 


for  orchards  were  built 
of  wood,  but  the  steady 
increase  in  the  price  of 
lumber  and  the  decrease 
in  the  price  of  Portland 

cement  have  induced  many  fruit  growers  to  use  cement  in  tt.A 
When  built  of  wood,  the  length  of  the  sections  varies  from  1- 
20  feet,  16  feet  being  the  most  common.  The  bottom  width  nm* 

404 


Fig.  11. 


-Section  of  wooden  head  flume,  showing 
opening  and  gate. 


16 


IRRIGATION  OF  ORCHARDS. 


from  6  to  12  inches,  while  the  depth  is  usually  1  to  2  inches  less. 
Redwood  lumber  If  inches  thick  is  perhaps  the  best  for  the  bottom 
and  sides,  and  joists  of  2  by  4  inch  pine  or  fir  are  commonly  used  for 
yokes  which  are  spaced  4  feet  centers.  Midway  between  the  yokes 
auger  holes  are  bored  and  the  flow  through  these  openings  is  con¬ 
trolled  in  the  manner  shown  in  figures  11  and  12.  A  2-inch  fall 
for  each  hundred  feet  may  be  regarded  as  a  suitable  grade  for  head 
flumes,  but  it  often  happens  that  the  slope  of  the  land  is  much  greater 
than  this,  in  which  case  low  checks  are  placed  in  the  bottom  of  the 
flume  at  each  opening,  as  shown  in  figure  12. 

A  head  flume  composed  of  cement,  sand,  and  gravel  costs  as  a  rule 
about  twice  as  much  as  a  wooden  flume  of  the  same  capacity,  but  the 
early  decay  of  wood,  especially  if  it  comes  in  contact  with  earth,  makes 
the  cement  flume  cheaper  in  the  end.  By  means  of  a  specially  de¬ 
signed  machine,  which  is  patented,  cement  mortar  composed  of  one 

part  cement  to  about  six 
parts  of  coarse  sand  is  fed 
into  a  hopper  and  forced 
by  lever  pressure  into  a  set 
of  guide  plates  of  the  form 
of  the  flume.  Such  flumes 
are  made  in  place  in  one 
continuous  line  across  the 
upper  margin  of  the  or¬ 
chard  tract.  After  the 
flume  is  built  and  before 
the  mortar  has  become 
hard,  small  tubes  from  f 

Fig.  12. — The  use  of  low  check  in  head  flume.  .  ,  .  ,. 

to  14  inches  m  diameter, 
the  size  depending  somewhat  on  the  size  of  the  flume,  are  inserted 
in  the  side  next  the  orchard.  The  flow  through  these  tubes  is 
regulated  by  zinc  slides  shown  in  figure  12.  Flumes  of  this  kind 
are  made  in  five  sizes,  the  smallest  being  G  inches  on  the  bottom  in 
the  clear  and  the  largest  14  inches. 

At  a  slightly  greater  cost  a  stronger  flume  can  be  built  by  the  use 
of  molds.  The  increased  strength  is  derived  from  a  change  in  the 
mixture.  In  the  machine-made  flume  the  mixture  of  one  part  cement 
to  five  or  six  parts  of  sand  is  lacking  in  strength,  for  the  reason 
that  there  is  not  enough  cement  to  fill  all  the  open  spaces  in  the  sand. 
In  using  molds  medium-sized  gravel  can  be  added  to  the  sand 
and  the  mixture  resembles  that  of  the  common  rich  concrete.  Sucli 
flumes  can  be  built  of  almost  any  size  from  a  bottom  width  of  10> 
inches  to  one  of  40  inches  and  from  a  depth  of  8  inches  to  one  of  24 
inches,  but  when  the  section  is  increased  beyond  about  240  square 

404 


IRRIGATION  OF  ORCHARDS. 


17 


inches  it  pays  better  to  slope  the  sides  outward  and  adopt  the  form 
of  the  cement-lined  ditch.  At  present  (March,  1910)  the  cost  of 
rich  concrete  in  place  would  be  about  $9  per  cubic  yard  for  the  larger 


Fig.  13. — Common  sizes  of  concrete  head  flumes. 


flumes  and  $10.50  for  the  smaller  sizes.  The  quantity  of  concrete 
required  per  linear  foot  of  flume  depends  on  its  size  and  the  thickness 
of  its  sides  and  bottom.  The  dimensions  given  in  figure  13  are  for 
light  rather  than  for  heavy 
flumes  and  are  designed  for 
localities  where  there  is  little 
frost. 

For  large  head  flumes  and 
laterals,  many  fruit  growers 
first  carefully  prepare  an 
earthen  ditch  which  has  car¬ 
ried  water  for  at  least  one 
season  and  afterwards  line 
the  inner  surface  with  cement  concrete.  Figure  14  shows  a  section 
of  such  a  ditch. 

Several  years  ago  3,200  linear  feet  of  head  ditches  were  lined  for 
26^  cents  per  foot;  they  were  14  inches  on  the  bottom  with  18-inch 
sides  and  a  2-inch  lining.  The  cement  cost  $2.85  per  barrel,  gravel 
75  cents  per  yard,  and  labor  $1.75  to  $2.50  per  day. 

Pipes  and  Standpipes. 

Head  flumes,  being  placed  on  the  surface  of  the  ground,  interfere 
with  the  free  passage  of  teams  in  cultivating,  irrigating,  and  harvest¬ 
ing  the  crop.  Dead  leaves  from  shade  and  fruit  trees  also  clog  the 
small  openings  in  the  flumes.  These  and  other  objections  to  flumes 
have  induced  many  fruit  growers  of  southern  California  to  conve} 
the  water  in  underground  pipes  and  distribute  it  through  standpipes 
placed  at  the  heads  of  the  rows  of  trees.  Both  cement  and  clay  pipes 
are  used  for  this  purpose. 


Fig.  14. — Earthen  head  ditch  lined  with  concrete. 


41647— Bull.  404—10 


3 


18 


IRRIGATION  OF  ORCHARDS. 


The  former  are  usually  molded  in  2-foot  lengths,  with  beveled  lap 
joints,  and  consist  of  a  1  to  3  or  1  to  4  mixture  of  cement  and 

fine  gravel  and  sand. 
The  most  common 

Turnout  Stand _  . 

Private  Lotero/  _ _ _  sizes  are  (*),  8,  10,  and 


Weir 
Box  X 


£ 


Ss 


ok 


tin 

<c£ 


M 


w . m 


M  M  M 


Overf/ow 

Stand 


m 


jw 


m 


,3 


"m 


iii 


Overf/ow 

Stand 


m 


Fig.  15. — The  use  of  pipes  in  furrow  irrigation. 


12  inches  in  diam- 
— -  eter,  having  a  thick- 

—  ness  of  shell  in  the 

—  12-inch  pipe  of  1^ 

—  inches  which  is  re- 

—  duced  to  a  trifle  more 

—  than  1  inch  in  the 
6-inch  pipe.  Piping 

—  of  this  kind,  when 
well  made  and  care- 

—  fully  laid,  will  with- 

—  stand  a  head  of  10 

—  to  16  feet.  The  clay 

—  pipe  is  similar  to 

—  that  used  in  cities  for 

—  sewers  and,  having 
stronger  joints,  with¬ 
stands  a  greater  pres¬ 
sure  but  costs  more. 

A  line  of  pipe  is  laid  about  2  feet  below  the  surface  from  the  feed 
main  and  measuring  box  across 
the  top  of  the  orchard,  and  as  each 
row  of  trees  is  passed  a  stand¬ 
pipe  is  inserted.  The  general  plan 
is  shown  in  outline  in  figure  15. 

Various  devices  are  employed  to 
convey  the  water  from  the  pipe  to 
the  surface  of  the  ground  at  the 
head  of  each  tree  row  and  divide 
it  up  evenly  among  4  to  6  furrows. 

One  of  the  most  common  consists 
of  a  series  of  standpipes,  the  top 
of  each  set  rising  to  the  same 
elevation.  At  each  change  of  ele- 
vation  special  standpipes  are  used 
and  in  these  are  inserted  gates  pro¬ 
vided  with  overflows.  The  man¬ 
ner  of  distributing  the  water  from 
a  standpipe  to  the  furrows  of  any  one  row  is  shown  in  figure  16. 

404 


Fig.  16. — Section  of  standpipe  outlined 
in  figure  15. 


IRRIGATION  OF  ORCHARDS.  19 

Occasionally  a  high-pressure  pipe  is  substituted  for  cement  and 
clay.  This  is  tapped  at  the  head  and  in  line  with  each  row  of  trees, 
and  a  small  galvanized-iron  pipe  is  inserted.  These  standpipes  are 
capped  by  an  ordinary  valve  which  regulates  the  flow  to  each  row 
of  trees.  This  method  is  shown  in  operation  in  figure  17,  where  a 
young  orchard  is  being  irrigated  from  f-inch  galvanized-iron  stand¬ 
pipes  connected  to  a  3-inch  wooden  pipe. 

Making’  Furrows. 


The  length  of  the  furrow  is  often  governed  by  the  size  of  the 
orchard.  The  rows  of  citrus  trees  seldom  exceed  40  rods  in  length, 

o  7 


Fig.  17. — Method  of  irrigating  from  iron  standpipes  connected  with  pressure  pipes. 


but  the  apple  orchards  of  the  Northwest  are  larger  as  a  rule.  Even 
in  large  tracts  it  is  doubtful  if  it  ever  pays  to  run  water  in  furrovs 
more  than  about  600  feet.  Where  the  soil  is  open  and  water  sinks 
readily  through  it,  short  furrows  should  be  used,  otherwise  much 
water  is  lost  in  deep  percolation  on  the  upper  part  of  the  tract.  1  i  of. 
H.  Culbertson,  of  San  Diego  County,  Cal.,  after  a  careful  investiga- 
tion  of  this  subject  has  reached  the  conclusion  that  on  sand\  oi 
gravellv  soil  having  a  steep  slope  the  proper  length  of  funovs  is 
200  feet,  while  on  heavier  soils  and  flatter  slopes  the  length  may  Ini 

increased  to  600  feet.  .  . 

The  grade  of  furrows  varies  quite  widely.  In  flat  valleys  it  is 

often  not  possible  to  obtain  a  fall  greater  than  1  inch  to  i  t 
feet,  while  on  steep  slopes  the  fall  may  reach  20  inches  per  100  feet. 

404 


20 


IRRIGATION  OF  ORCHARDS. 


Oil  ordinary  soils  a  grade  of  3  to  4  inches  is  to  be  preferred,  and  where 
the  fall  exceeds  8  to  10  inches  to  100  feet  the  trees  should  be  set  out 
in  such  a  way  as  to  decrease  the  slope  of  the  furrows. 

The  number  of  furrows  in  orchards  depends  on  the  age  of  the 
trees,  the  space  between  the  rows,  the  depth  of  furrow,  and  the 
character  of  the  soil.  Nursery  stock  is  irrigated  by  one  or  two  fur¬ 
rows  and  young  trees  by  two  to  four.  A  common  spacing  for  shal¬ 
low  furrows  is  2J  feet,  while  deeper  furrows  are  made  3  to  4  feet 
apart.  The  general  trend  of  orchard  practice  is  toward  deep  rather 
than  shallow  furrows,  a  depth  of  8  inches  being  frequently  used. 


Fig.  18. — Making  furrows  in  orchard. 


The  furrowing  implement  most  commonly  used  by  the  orcliardists 
of  Orange  County,  Cal.,  consists  of  a  sulky  frame  to  which  are  at¬ 
tached  two  or  three  double  moldboard  plows.  Those  who  prefer  a 
small  number  of  deep  furrows  use  a  12  to  14  inch  corn  lister.  In 
figure  18  is  shown  a  furrower  made  by  attaching  an  arm  to  a  culti¬ 
vator  and  then  fastening  two  shovels  to  the  arm.  In  the  view  the 
space  between  the  furrows  is  4-J  feet  and  the  depth  is  regulated  by  the 
lever  arm  of  the  cultivator. 

Applying-  Water  to  Furrows. 

In  the  Payette  Valley,  Idaho,  200  or  more  miner’s  inches  are  turned 
into  the  head  ditch  and  divided  up  by  means  of  wooden  spouts  into 

404 


IRRIGATION  OF  ORCHARDS. 


21 


a  like  number  of  furrows.  On  steep  ground  much  smaller  streams  are 
used.  The  length  of  the  furrow  varies  from  300  feet  on  steep  slopes 
to  GOO  feet  and  more  on  flat  slopes.  The  time  required  to  moisten  the 
soil  depends  on  the  length  of  the  furrow  and  the  nature  of  the  soil. 
In  this  locality  it  varies  from  3  to  36  hours. 

J.  H.  Foreman  owns  20  acres  of  bearing  orchard  under  the  Sunny- 
side  Canal  in  the  Yakima  Valley,  Washington,  and  waters  it  four 

times  in  each  season  with  14  _ _ 

miner’s  inches  (0.35  cubic 
foot  per  second) .  He  makes 
three  furrows  between  the 
rows,  which  are  40  rods  long. 


The  total  supply  is  applied 
to  one-lialf  the  orchard  (10 
acres)  and  kept  on  48  hours. 

On  the  clayey  loams  of 
the  apple  orchards  on  the 

r  „  .  Fig.  19. — Furrow  irrigation,  showing  dry  spaces. 

east  bench  ol  the  Fitter 

Root  River,  Montana,  Prof.  R.  W.  Fisher  has  found,  as  a  result 
of  experimenting,  that  it  requires  from  12  to  18  hours  to  moisten 
the  soil  in  furrow  irrigation  4  feet  deep  and  3  feet  sideways. 

In  1908  Mr.  Struck,  of  Hood  River,  Oregon.,  irrigated  3  acres  of 
apple  trees  in  furrows  350  feet  long,  spaced  3  feet  apart.  About  a 
miner’s  inch  of  water  was  turned  into  each  alternate  furrow  from  a 
wooden  head  flume  (fig.  11,  p.  15)  and  kept  on  for  about  48  hours. 
After  the  soil  had  become  sufficiently  dry  it  was  cultivated,  and  in  8  or 

10  days  thereafter  water 
was  turned  into  the  alter¬ 
nate  rows,  which  were 
left  dry  during  the  first 
irrigation. 

For  the  most  part,  the 
furrows  are  made  parallel 
to  the  rows  of  trees.  An 
arrangement  of  this  kind 

- - - -  is  satisfactory  in  young 

Fig.  20.— Cross  furrowing  the  dry  spaces.  orchards,  but  as  the  trees 

reach  maturity  their  branches  occupy  more  of  the  open  space  be- 
tween  the  rows  and  prevent  the  making  of  furrows  near  the  trees. 
This  is  shown  in  figure  19  where  a  space  of  6  to  12  feet  square, 
according  to  the  size  of  the  trees,  is  not  furrowed.  This  space 
usually  becomes  so  dry  that  it  is  worthless  as  a  feeding  giomm 
for  roots.  In  order  to  moisten  these  dry  spots,  a  larger  stream  is 
often  carried  in  the  two  furrows  next  to  each  low  ol  U<i 


404 


22 


IRRIGATION  OF  ORCHARDS. 


surplus  is  led  across  in  short  furrows  in  the  manner  shown  in  figure 
20.  Instead  of  continuing  straight  and  cross  furrows,  as  is  done  in 
figure  20,  use  is  frequently  made  of  diagonal  furrows,  figure  21,  to 
moisten  the  dry  space  between  the  trees.  This  last  method  is  best 
adapted  to  grades  of  5  inches  to  the  100  feet  or  more. 

A  method  and  the  cost  of  one  irrigation  is  described  as  follows : 

The  implement  used  to  make  furrows  consists  of  three  shovels 
•  attached  to  a  beam  which  is  mounted  on  a  pair  of  low  wheels.  The 

driver  sits  on  a  riding 
seat  and  by  operating  a 
lever  can  regulate  the 
depth  of  the  furrows.  A 
man  and  two  horses  will 
furrow  out  10  acres  in  a 
day.  For  a  distance  of 
150  feet  from  the  top  of 
the  orchard  the  furrows 
are  straight.  They  are 
then  zigzagged  to  within 
60  or  70  feet  of  the  bottom,  where  the  last  three  rows  of  trees  are 
irrigated  by  basins  which  catch  the  surplus.  In  the  case  described 
the  depth  of  furrow  was  6  inches,  length  800  feet,  and  distance  apart 
3  feet.  A  head  of  50  miner’s  inches  (1  cubic  foot  per  second)  was 
used  on  10  acres.  The  streams  when  first  turned  into  the  furrows 
averaged  about  2  miner’s  inches,  but  as  the  water  approached  the 
lower  end  they  were  reduced  to  1  miner’s  inch  or  less,  and  this  flow 
was  run  in  each  furrow  for  12  to  24  hours. 

The  items  of  cost  for  10  acres  were  as  given  below : 


Making  furrows  and  basins _ $6.  50 

Irrigating _  3.  00 

Fifty  inches  of  water,  24  hours,  at  40  cents  an  hour _  9.  60 

Rent  of  water  stock _ 12.00 


Total _ 31. 10 

THE  BASIN  METHOD. 


Orchards  are  sometimes  irrigated  by  first  forming  ridges  midway 
between  the  rows  in  tAvo  directions  at  right  angles  to  each  other.  This 
divides  up  the  tract  into  a  large  number  of  squares  with  a  tree  in 
the  center  of  each,  as  may  be  observed  in  figure  22. 

When  the  ground  is  hard  or  covered  with  Aveeds,  a  disk  plow  is 
first  run  betAveen  the  roAvs  and  then  the  loosened  earth  is  formed  into 
a  ridge  by  a  riclger.  If  the  soil  is  light,  sandy,  and  free  from  Aveeds, 
the  disking  is  not  necessary.  Ridgers  are  made  in  various  Avays  of 
both  AA7ood  and  steel  or  some  combination  of  both.  A  common  kind 
is  shown  in  figure  23.  It  consists  of  two  deep  runners  14  to  18  inches 

404 


IRRIGATION  OF  ORCHARDS. 


23 


Fig.  22. — Basin  method  of  irrigation. 


high,  2  inches  thick,  and  6  to  8  feet  long.  These  runners  are  shod 
with  steel  which  extends 

part  way  up  the  inner  side. 

They  are  4  to  5  feet  apart 
at  the  front  end  and  ta¬ 
pered  to  1G  to  24  inches  at 
the  rear.  The  runners  are 
held  in  position  by  cross 
pieces  on  top,  a  floor,  and 
straps  of  steel  in  the  man¬ 
ner  shown.  The  height  of 
the  ridges  varies  with  the 
depth  of  water  applied, 
which  is  from  4  to  9  inches. 

The  ridges  should  be  sev¬ 
eral  inches  above  the  surface  of  the  water  when  a  basin  is  flooded. 

Several  methods  of  flood¬ 
ing  basins  are  practiced. 
In  one  a  ditch  is  run  from 
the  supply  ditch  at  the 
head  through  each  alter¬ 
nate  row  space  and  the 
basins  on  each  side  are 
flooded  in  pairs  beginning 
with  the  lowest.  This  plan 
is  shown  in  outline  in 
figure  22.  In  the  other 
method  water  is  allowed  to  flow  through  openings  into  each  basin 
of  a  tier  in  a  zigzag  course  from  the 
top  to  the  bottom  of  the  orchard.  In 
this  plan  the  upper  basins  receive  the 
most  water.  Under  gravity  canals, 
where  water  is  abundant,  the  water  is 
turned  into  the  upper  basin  until  it  is 
full,  when  it  overflows  into  the  next, 
and  so  on  down  the  tier.  The  irrigator 
then  begins  at  the  lower  end  and  repairs 
the  breaks,  leaving  each  basin  full  of 
water. 

THE  CHECK  METHOD. 


Fig.  23. — Ridger  used  in  basin  irrigation. 


4 


I 


V 


Fig.  24. — Combination  of  check  and 
furrow  methods. 


Where  this  method  is  practiced  it 
frequently  happens  that  land  on  which 
alfalfa  has  been  grown  is  planted  to  fruit  trees.  In  plowing  down 

404 


24 


IRRIGATION  OF  ORCHARDS. 


the  alfalfa  and  setting  out  the  trees,  the  levees  undergo  little  change 
and  the  checks  can  be  flooded  if  it  is  considered  best.  A  better 
plan  is  to  furrow  the  floor  of  each  check  as  shown  in  figure  24.  The 
water  is  admitted  through  the  check  box  which  was  used  for  the 
alfalfa  and  conducted  into  a  short  head  ditch,  from  which  it  is  dis¬ 
tributed  to  the  furrows.  The  chief  objection  to  this  method  is  that 
the  checks  are  too  small  for  orchard  tracts  in  furrow  irrigation. 

TIME  TO  IRRIGATE  ORCHARDS. 

The  best  orchardists  believe  that  frequent  examinations  of  the 
stem,  branches,  foliage,  and  fruit  are  not  enough.  The  roots  and 
soil  should  likewise  be  examined.  The  advice  of  such  men  to  the 
inexperienced  is:  Find  out  where  the  bulk  of  the  feeding  roots  is 
located,  ascertain  the  nature  of  the  soil  around  them,  and  make 
frequent  tests  as  to  the  moisture  which  it  contains.  In  a  citrus 
orchard  of  sandy  loam  samples  are  taken  at  depths  of  about  3  feet, 
and  the  moisture  content  determined  by  exposing  the  samples  to  a 
bright  sun  for  the  greater  part  of  a  day.  It  is  considered  that  G  per 
cent  by  weight  of  free  water  is  sufficient  to  keep  the  trees  in  a  vigorous 
condition. 

Doctor  Loughridge,  of  the  University  of  California,  in  his  experi¬ 
ments  at  Riverside,  Cal.,  in  June,  1905,®  found  an  average  of  3.5  per 
cent  in  the  upper  2  feet  and  an  average  of  G.1G  per  cent  below  this  * 
level  in  an  orchard  which  had  not  been  irrigated  since  October  of  the 
preceding  year.  It  had  received,  however,  a  winter  rainfall  of  about 
1G  inches.  On  examination  it  was  found  that  the  bulk  of  the  roots 
lay  between  the  first  and  fourth  foot.  These  trees  in  June  seemed  to 
be  merely  holding  their  own.  When  irrigated  July  7  they  began  to 
make  new  growth.  A  few  days  after  the  water  was  applied  the 
percentage  of  free  water  in  the  upper  4  feet  of  soil  rose  to  9.G4  per 
cent.  The  results  of  these  tests  seem  to  indicate  that  the  percentage 
by  weight  of  free  moisture  should  range  between  5  and  10  per  cent 
in  orchard  loams. 

Many  fruit  growers  do  not  turn  on  the  irrigation  stream  until  the 
trees  begin  to  show  visible  signs  of  suffering,  as  a  slight  change  in 
color  or  a  slight  curling  of  the  leaves.  In  thus  waiting  for  these 
signals  of  distress,  both  trees  and  fruit  are  liable  to  be  injured.  On 
the  other  hand,  the  man  who  ignores  these  symptoms  and  pours  on  a 
large  quantity  of  water  whenever  he  can  spare  it,  or  when  his  turn 
comes,  is  apt  to  cause  greater  damage  by  an  overdose  of  water. 


404 


a  U.  S.  Dept.  Agr.,  Office  Expt.  Stas.  Bill.  20o. 


IRRIGATION  OF  ORCHARDS. 


25 


NUMBER  OF  IRRIGATIONS  PER  SEASON. 

For  nearly  half  the  entire  year  the  fruit  trees  of  Wyoming  and 
Montana  have  little  active,  visible  growth,  whereas  in  the  citrus  dis¬ 
tricts  of  California  and  Arizona  the  growth  is  continuous.  A  tree 
when  dormant  gives  off  moisture,  but  the  amount  evaporated  from 
both  soil  and  tree  in  winter  is  relatively  small,  owing  to  the  low  tem¬ 
perature,  the  lack  of  foliage,  and  feeble  growth.  A  heavy  rain  which 
saturates  the  soil  below  the  usual  covering  of  soil  mulch  may  take 
the  place  of  one  artificial  watering,  but  the  light  shower  frequently 
does  more  harm  than  good.  The  number  of  irrigations  likewise  de¬ 
pends  on  the  capacity  of  the  soil  to  hold  water.  If  it  readily  parts 
with  its  moisture,  light  but  frequent  applications  will  produce  the 
best  results,  but  if  it  holds  water  well  a  heavy  application  at  longer 
intervals  is  best,  especially  when  loss  by  evaporation  from  the  soil  is 
prevented  by  the  use  of  a  deep  soil  mulch. 

In  the  Yakima  and  Wenatchee  fruit-growing  district  of  Washing¬ 
ton  the  first  irrigation  is  usually  given  in  April  or  early  in  May. 
Then  follow  three  to  four  waterings  at  intervals  of  20  to  30  days.  At 
Montrose,  Colo.,  water  is  used  three  to  five  times  in  a  season.  At 
Payette,  Idaho,  the  same  number  of  irrigations  is  applied,  beginning 
about  June  1  in  ordinary  seasons  and  repeating  the  operation  at 
the  end  of  30-day  intervals.  As  a  rule,  the  orchards  at  Lewiston, 
Idaho,  are  watered  three  times,  beginning  about  June  15.  From  two  to 
four  waterings  suffice  for  fruit  trees  in  the  vicinity  of  Boulder,  Colo. 
The  last  irrigation  is  given  on  or  before  September  5,  so  that  the  new 
wood  may  have  a  chance  to  mature  before  heavy  freezes  occur.  In 
the  Bitter  Root  Valley,  Montana,  young  trees  are  irrigated  earlier  and 
oftener  than  mature  trees.  Trees  in  bearing  are,  as  a  rule,  irrigated 
about  July  15,  August  10,  and  August  20  of  each  year.  In  San  Diego 
County,  Cal.,  citrus  trees  are  watered  six  to  eight  times,  and  deciduous 
trees  three  to  four  times  in  a  season. 


DUTY  OF  WATER  IN  ORCHARD  IRRIGATION. 

The  duty  of  water  for  1  acre  as  fixed  by  water  contracts  varies  all 
the  way  from  one-fortieth  to  one  four-hundredths  of  a  cubic  loot  per 
second.  In  general,  the  most  water  is  applied  in  districts  that  require 
the  least.  Wherever  water  is  cheap  and  abundant  the  tendency  seems 
to  be  to  use  large  quantities,  regardless  of  the  requirements  ot  the 
fruit  trees.  In  Wyoming  the  duty  of  water  is  seldom  less  than  at  the 
rate  of  a  cubic  foot  per  second  for  TO  acres.  In  parts  oi  southci  n  (  il- 
i for nia  the  same  quantity  of  water  not  infrequently  serves  400  acres, 


404 


26 


IRRIGATION  OF  ORCHARDS. 


yet  the  amount  required  by  the  fruit  trees  of  the  latter  locality  is  far 
in  excess  of  that  of  the  former. 

In  recent  years  the  tendency  all  over  the  West  is  toward  a  more  eco¬ 
nomical  use  of  water,  and  even  in  localities  where  water  for  irrigation 
is  still  reasonably  low  in  price  it  is  rare  that  more  than  2J  acre-feet 
per  acre  is  applied  in  a  season.  This  is  the  duty  provided  for  in  the 
contracts  of  the  Bitter  Root  Valley  Irrigation  Company,  of  Montana, 
which  has  40,000  acres  of  fruit  lands  under  ditch.  Since,  however, 
the  water  user  is  not  entitled  to  receive  more  than  one-half  of  an  acre- 


-Avcrage  duty  per  month  under  Riverside  Water  Company,  December  1,  1901,  to 

November  30,  1908. 


foot  per  acre  in  any  one  calendar  month,  it  is  only  when  the  growing 
season  is  long  and  dry  that  he  requires  the  full  amount. 

In  the  vicinity  of  Boulder,  Colo.,  the  continuous  flow  of  a  cubic  foot 
per  second  for  105  days  serves  about  112  acres  of  all  kinds  of  crops. 
This  amount  of  water,  if  none  were  lost,  would  cover  each  acre  to  a 
depth  of  1.0  feet.  In  other  words,  the  duty  of  water  is  a  trifle  less 
than  2  acre-feet  per  acre. 

In  1908,  the  depth  of  water  used  on  a  21^-acre  apple  orchard  at 
Wenatchee,  Wash.,  was  measured  and  found  to  be  23  inches.  The 
trees  were  7  years  old  and  produced  heavily.  This  orchard  was 
watered  five  times,  the  first  on  May  13  and  the  last  on  September  23. 
In  San  Diego  County,  Cal.,  one  miner’s  inch  (one-fiftieth  of  a  cubic 

404 


IRRIGATION  OF  ORCHARDS.  27 

foot  per  second)  irrigates  from  G  to  7  acres  near  tliQ  coast  where  the 
air  is  cool  and  evaporation  low,  but  20  miles  or  so  inland  the  same 
amount  of  water  is  needed  for  about  4  acres. 

On  the  sandy  loam  orchards  of  Orange  County,  Cal.,  it  has  been 
demonstrated  that  2  acre-inches  every  sixty  days  is  insufficient  to 
keep  bearing  trees  in  good  condition.  The  rainfall  of  this  locality 
averages  somewhat  less  than  12  inches  per  annum,  but  about  95  per 
cent  of  the  total  falls  between  November  and  May,  inclusive. 

The  most  reliable  and  in  many  ways  the  most  valuable  records 
pertaining  to  duty  of  water  on  orchards  have  been  obtained  by  the 
water  companies  of  Riverside  County,  Cal.  Here  more  or  less  irri¬ 
gation  water  is  used  every  month  of  the  year.  Figure  25  is  a  graphic 
representation  of  the  average  amount  of  water  used  per  month  in 
a  period  of  seven  years  by  the  Riverside  Water  Company  in  irri¬ 
gating  about  9,000  acres,  of  which  nearly  6,000  acres  are  planted  to 
oranges  and  the  balance  to  alfalfa.  The  figures  given  in  the  diagram 
represent  depth  in  feet  over  the  surface  watered.  In  the  following 
table  is  given  the  average  duty  of  water  per  month  in  acre-feet  per 
acre  under  the  same  system  from  December  1,  1901,  to  November  30, 
1908,  a  period  of  seven  years.  The  table  also  includes  the  average 
monthly  rainfall  at  Riverside,  Cal.,  for  the  same  period,  and  adding 
the  quantity  of  water  applied  in  irrigation  in  any  one  month  to  the 
rainfall  of  that  month  gives  the  total  moisture  received  by  the  soil. 

Water  used  under  Riverside  Water  Company's  system  {1901-1908) . 


Month. 

Average 
depth 
per  acre. 

Average 

rainfall. 

Total 

water 

applied. 

Month. 

Average 
depth 
per  acre. 

Average 

rainfall. 

Total 

water 

applied. 

December . 

January . 

February  . 

March . 

April . 

Mav . 

June . 

Feet. 

0.159 

.123 

.046 

.078 

.177 

.291 

.274 

Feet. 

0.109 
.170 
.190 
.316 
.068 
.  023 
.003 

Feet. 

0.  268 
.293 
.236 
.394 
.245 
.314 
.277 

July . 

August . 

September . 

October . 

November . 

Total . 

Feet. 
0.272 
.  269 
.  243 
.189 
.169 

Feet. 

0. 002 

.015 
.043 
.  073 

Feet. 

0. 274 
.269 
.258 
.  232 
.242 

2. 29 

1.01 

3.  30 

EVAPORATION  LOSSES  FROM  ORCHARD  SOILS. 

A  light  shower  followed  by  warm  sunshine  may  refresh  the  foliage 
of  fruit  trees,  but  its  effect  on  the  soil  is  more  likely  to  be  injurious 
than  otherwise.  A  brief,  pelting  rain  followed  by  sunshine  forms  a 
crust  on  the  surface  of  most  soils,  and  if  this  is  not  soon  broken  up  b\ 
cultivation  it  checks  the  free  circulation  of  air  in  the  soil  and  a  ho 
tends  to  increase  the  amount  of  water  evaporated. 

It  has  been  found  a  that  the  amount  of  moisture  held  b\  the  M)il, 
the*  temperature  of  both  soil  and  air,  and  the  rate  of  wind  motion 


404 


a  U.  S.  Dept.  Agi\,  Office  Expt.  Stas.  Bui.  ITT. 


28 


IRRIGATION  OF  ORCHARDS. 


are  the  chief  factors  in  the  evaporation  of  water  from  soils.  The 
influence  of  moisture  is  shown  in  the  following  figures,  obtained  from 
tank  experiments  made  at  Tulare,  Cal.,  in  1904: 


Evaporation  from  Tulare  soils  which  received  different  amounts  of  water ,  June 

15  to  September  15,  190.[ ). 


Numbers  of  tanks. 

Amount 
of  water 
applied, 
inches. 

Loss  by  evapora¬ 
tion. 

Inches. 

Per  cent. 

1  and  2 . 

0.0 

0.45 

3  and  4 . 

3.3 

3.5 

106.0 

5  and  6 . 

4.9 

4.6 

94.0 

Numbers  of  tanks. 

Amount 
of  water 
applied, 
inches. 

Loss  by  evapora¬ 
tion. 

Inches. 

Per  cent. 

7  and  8 . 

6.6 

5.5 

83.6 

9  and  10 . 

8.2 

6.6 

80.0 

11  and  12 . 

9.8 

7.9 

79.5 

The  results  of  other  experiments  have  shown  that  when  the  water 
is  applied  to  the  surface  of  orchard  soils  the  loss  by  evaporation  is 
very  great  so  long  as  the  top  layer  remains  moist.  Even  in  light  irri- 


1904  1905 

Fig.  26. — Relation  between  temperature  and  evaporation  from  a  water  surface  at 

Tulare,  Cal. 


gations  this  loss  in  forty-eight  hours  after  the  water  is  put  on  may 
amount  to  from  10  to  20  per  cent  of  the  volume  applied.  In  order  to 
reduce  this  loss  and  moisten  the  soil  around  the  roots  of  trees,  the 
practice  of  running  small  streams  of  water  in  deep  furrows  has 
become  quite  common.  In  applying  water  in  this  way  the  top  soil 
remains  at  least  partially  dry,  the  bulk  of  the  water  soon  passes 
beyond  the  first  foot,  and  the  surface  can  be  cultivated  soon  after  the 
water  is  turned  off. 

The  well-known  effect  of  temperature  on  evaporation  is  shown  in 
figure  26,  The  dotted  line  shows  the  mean  monthly  temperatures 

404 


IRRIGATION  OF  ORCHARDS. 


29 


Tulare,  Cal.,  from  January  1,  1904,  to  December  31,  1905.  and 
the  solid  line  the  monthly  evaporation  from  a  water  surface  for  the 
same  time. 


EFFECT  OF  SOIL  MULCHES  IN  CHECKING  EVAPORATION. 

The  effect  on  evaporation  of  a  layer  of  dry  granular  soil  when 
placed  above  moist  soil  has  been  shown  by  a  series  of  experiments 
conducted  in  tanks  by  irrigation  investigations  of  this  Office.  These 
tanks  are  water- jacketed  and  placed  in  the  open  under  normal  condi¬ 
tions  as  regards  sunshine,  wind,  and  temperature.  Each  tank  holds 
about  three-fourths  of  a  ton  of  soil  and  is  weighed  at  stated  intervals 
in  a  manner  shown  in  figure  27.  The  results  of  experiments  made  at 
Davis,  Cal.,  in  1908  are  given  in  the  following  table: 


Evaporation  from  soils  protected  bp  different  depths  of  soil  mulch  at  Davis, 

Cal.,  September  1  to  October  3,  1908.a 


• 

No  mulch, 
tanks  land  2. 

3-inch  mulch, 
tanks  3  and  4. 

6-inch  mulch, 
tanks  5  and  6. 

9-inchmulch, 
tanks  7  and  8. 

Average  weight  of  tanks,  Sept.  1... pounds.. 

1, 104. 7 

1, 090. 0 

1, 082. 0 

1, 085. 2 

Per  ct. 

Per  ct. 

Per  ct. 

Per  ct. 

Per  ct. 

Per  ct. 

Per  ct. 

Per  ct. 

Average  loss,  3  days,  Sept.  1  to  4 . 

Average  loss,  4  days,  Sept.  4  to  8 .  . 

16. 75 

17.83 

1.75 

1.86 

0.0 

0.0 

0.0 

0.0 

4.5 

4.79 

.75 

.80 

.25 

.27 

-  .5 

-  .53 

Average  loss,  3  days,  Sept.  8  to  11 . 

Average  loss,  4  days,  Sept.  11  to  15 . 

3.0 

1.5 

3.19 

1.  60 

2. 25 

2  5 

2.4 

2.66 

.75 

.80 

-  .25 

-  .27 

Average  loss,  18  days,  Sept.  15  to  Oct.  3 . 

8.0 

8. 52 

7.0 

7. 45 

4.  75 

5. 05 

2.25 

2.4 

Total  loss,  32  days,  Sept.  1  to  Oct.  3 . 

33. 25 

35.  93 

14. 25 

15.17 

5.  75 

6.12 

.  75 

.80 

a  U.  S.  Dept.  Agr.,  Yearbook  1908,  p.  468. 


The  soil  first  received  an  irrigation  of  0  inches  in  depth  over  the 
surface  and  in  the  tanks  which  had  no  mulch  over  one-third  of  this 
amount  was  evaporated  in  thirty-two  days,  while  less  than  1  per  cent 
was  evaporated  in  the  tanks  which  were  protected  by  a  9-inch  mulch. 

Similar  experiments  carried  on  at  Wenatchee,  Wash.,  in  June, 
1908,  showed  the  following  losses  in  twenty-one  days:  No  mulch,  14J 
per  cent  of  water  applied;  3-inch  mulch,  4  per  cent;  6-inch  mulch, 
2  per  cent ;  and  9-inch  mulch,  1  per  cent. 

From  the  foregoing  it  is  evident  that  western  orchardists  can  pre¬ 
vent  the  greater  part  of  the  evaporation  losses  by  cultivating  orchards 
to  a  depth  of  at  least  6  inches  as  soon  as  practicable  after  each  irri¬ 
gation. 

LOSS  OF  WATER  DUE  TO  PERCOLATION. 


In  the  preceding  paragraphs  attention  has  been  called  to  the  large 
amount  of  water  which  is  vaporized  from  warm,  moist  soil-, 
above  heading  calls  attention  to  another  loss  of  a  different  character. 
404 


30 


IRRIGATION  OF  ORCHARDS. 


In  all  modes  of  wetting  the  soil,  but  more  particularly  when  deep 
furrows  are  used  to  distribute  the  water,  a  part  is  liable  to  sink 
beyond  the  deepest  roots.  As  a  rule,  the  longer  the  furrow  the 
greater  is  the  loss  from  this  cause.  In  furrows  about  one-eighth  of 
a  mile  long  Doctor  Loughridge  found  in  his  experiments  at  Riverside, 
Cal.,°  that  in  some  parts  of  the  orchard  the  soil  was  wet  as  a  result 
of  a  recent  irrigation  to  depths  of  20  to  20  feet,  while  in  other  parts 
the  moisture  had  not  penetrated  beyond  the  third  foot. 

One  of  the  best  ways  of  finding  out  whether  much  water  is  lost 

by  deep  percolation  is  to 
dig  cross  trenches  as  deep 
as  the  feeding  roots  go. 
The  moisture  which  passes 
the  deepest  roots  in  its 
downward  course  may  be 
considered  wasted. 

An  example  of  fairly 
even  and  desirable  mois¬ 
ture  distribution  from  fur¬ 
rows  is  shown  in  Sections 
XI  and  XII  of  figure  28, 
where  the  three  curved 
lines  show  the  margins  of 
the  wetted  soil  at  the  end 
of  one,  two,  and  three 
days,  respectively. 


REMOVAL  OF  WASTE 
WATER. 


Fig.  27. — Tank  experiments  at  Reno,  Nev.,  to  deter¬ 
mine  effect  of  soil  mulches  in  checking  evaporation. 


The  loss  of  water  is  not 
the  only  effect  of  deep 
percolation.  The  water 
which  escapes  in  this  and 
other  ways  usually  moves 


through  the  soil  at  a  rather  slow  rate  of  speed  until  it  reaches  some 
underground  body  of  water  at  a  lower  level.  In  case  orchards  have 
been  planted  at  these  lower  levels  when  the  subsoil  was  dry,  care 
should  be  exercised  in  observing  the  rise  of  the  ground-water  level. 


The  small  post-hole  auger  shown  in  figure  29  is  one  of  the  most  con¬ 
venient  tools  to  use  in  making  test  wells  to  keep  track  of  the  behavior 
of  the  ground  water.  Before  the  deepest  roots  of  the  fruit  trees  are 


U.  S.  Dept.  Agr.,  Office  Expt.  Stas.  Bui.  203. 


404 


Fig.  28. — Outlines  of  percolation  under  sixteen  furrows  in  orchard  58  under  the  Gage  Canal  Company,  Riverside,  Cal. 


IRRIGATION  OF  ORCHARDS 


31 


404 


32 


IRRIGATION  OF  ORCHARDS. 


submerged,  artificial  drainage  ought  to  be  provided.  Otherwise  the 
ground  water  will  at  first  lessen  the  yield  and  finally  destroy  the  trees. 

The  drainage  of  orchard  tracts  usually  progresses  in  more  or  less 
distinct  and  separate  stages.  When  the  ground  water  begins  to  be  a 

menace,  the  natural  ravines  in  the  vicinity  are 
cleared  of  weeds  and  other  rubbish  and  deep 
ened.  If  the  ground  water  continues  to  rise, 
the  open  drains  are  deepened  and  extended  or 
else  the  excess  water  is  withdrawn  through  cov¬ 
ered  drains.  Open  drains  in  orchards  occupy 
valuable  land,  obstruct  field  work,  and  are  ex¬ 
pensive  to  maintain.  Some  of  these  objections 
can  be  lessened  if  not  removed  by  locating 
such  drains  along  the  lower  boundary  of  the 
tract.  When  this  plan  is  followed,  covered 
drains  are  frequently  laid  among  the  trees  and 
discharge  into  the  open  drains.  Sometimes  the 
source  and  direction  of  the  waste  water  which 
is  waterlogging  an  orchard  can  be  traced  be¬ 
neath  the  surface,  In  this  event  it  is  well  to 
try  to  intercept  its  passage  before  it  reaches 
to  locate  ground-water  the  trees.  This  can  be  done  by  an  open  drain, 
leveL  but  a  covered  pipe  drain  of  the  required  size 

is  preferable.  Where  durable  lumber  is  cheap,  box  drains  similar 
to  that  shown  in  figure  30  may  be  used.  Where  lumber  is  high  in 
price,  it  will  be  more  economical  to  use  pipe  drains  made  of  either 
clay  or  cement.  The  former  is 
most  frequently  used  for  sizes 
ranging  from  4  to  8  inches  in 
diameter  and  the  latter  for  sizes 
10  inches  and  over.  The  clay  or 
tile  drains  are  made  1  foot  in 
length,  but  in  using  cement  for 
the  larger  sizes  the  length  may 
be  increased  to  2  and  even  3  feet. 

The  drainage  of  irrigated 
lands  differs  in  many  respects 
from  that  common  to  the  humid 
States  of  Iowa,  Illinois,  or  Ohio. 

In  irrigated  districts  the  drains 
are  larger  and  are  laid  deeper.  While  4-inch  tile  drains  may  be  used 
in  places,  6-inch  drains  are  to  be  preferred,  and  should  be  considered 
as  the  smallest  desirable  size.  The  depth  at  which  they  are  laid  ranges 
from  4  to  T  feet,  and  5  to  6  feet  are  required  for  orchards.  A  grade 


404 


IRRIGATION  OF  ORCHARDS. 


33 


of  5  feet  to  the  mile  is  about  the  least  that  should  be  used,  and 
wherever  practicable  it  should  be  increased  to  10  feet  to  the  mile. 

In  laying  drains  that  are  likely  to  become  clogged  with  silt  or 
roots,  or  both,  a  small  cable  is  laid  in  each  line,  and  at  distances  of 
300  to  500  feet  sand  boxes  similar  to  figure  31  are  placed  so  as  to 
facilitate  cleaning  the  tiles  with  suitable  wire  brushes. 


GROWING  CROPS  BETWEEN  THE  TREE  ROWS. 


OTOW 


The  large  majority  of  California  fruit  growers  do  not  o 
marketable  crops  between  the  trees.  They  believe  in  clean  culture, 
except  where  legumi¬ 


nous  crops  are  used  to 
renovate  and  fertilize 
the  soil.  From  the 
standpoint  of  the  large 
commercial  orchard 
and  the  well  to-do  pro¬ 
prietor,  this  practice 
has  much  to  recom¬ 
mend  it.  The  plant¬ 
ing  of  such  an  orchard 
is  regarded  as  a  long¬ 
time  investment.  Lit¬ 
tle  if  any  returns  are 
expected  for  the  first 
few  years,  but  when 
the  trees  approach  ma¬ 
turity  and  are  in  full 
bearing  the  anticipated 
profits  are  supposed  to 
compensate  the  owner 

for  all  the  lean  years.  Any  treatment,  therefore,  which  tends  to 
rob  the  soil  of  its  plant  food  when  the  trees  are  young  or  to  retard 
their  growth  is  pretty  certain  to  lessen  the  yields  and  the  consequent 
profits  in  later  years.  Prof.  E.  J.  Wickson,  director  of  the  Cali  oiiiia 
Experiment  Station,  tersely  expressed  the  prevailing  opinion  on  t 
question  in  California  in  his  work,  “California  Fruits  and  How  to 
Grow  Them,”  in  the  following  language:  “All  intercultures  are  a 
loan  made  by  the  trees  to  the  orchardist.  The  term  may  be  long  and 
the  rate  of  interest  low,  but  sooner  or  later  the  trees,  will  need  res  i 
tution  to  the  soil  of  the  plant  food  removed  by  intercropping 

Mr.  S.  W.  McCulloch,  who  controls  150  acres  of  cdri^ondnirdsm 

southern  California,  goes  further  in  stating..  is  a  <}» 


404 


34 


IRRIGATION  OF  ORCHARDS. 


mental  to  the  development  of  an  orchard  to  grow  crops  between  the 
trees.  In  some  cases  the  effect  is  not  marked  aside  from  securing  less 
rapid  growth,  but  it  will  affect  the  crops  of  fruit  for  several  years 
and  in  the  end  nothing  will  be  gained.’’ 

Notwithstanding  all  this,  the  poor  man  must  needs  make  the  loan 
or  his  children  mav  starve.  The  settler  on  a  small  tract  set  out  to 
young  trees  can  not  afford,  if  his  means  are  limited,  to  wait  four  or 
five  years  for  the  first  returns.  He  must  produce  crops  between  the 
rows,  and  the  question  for  him  to  consider  is  how  this  can  be  done 
with  the  least  possible  injury  to  the  trees.  A  plentiful  supply  of 
water  and  a  deep  rich  soil  are  the  essentials  of  intercropping.  In 
districts  that  depend  on  a  meager  rainfall  of  15  to  20  inches  per 
annum,  or  where  irrigation  water  is  both  scarce  and  costly,  the  prac¬ 
tice  becomes  of  doubtful  value  under  an}^  circumstances.  In  most 
of  the  fruit  districts  of  the  West  water  for  irrigation  is  still  reason¬ 
ably  low  in  price,  and  the  extra  amount  required  for  intercropping 
represents  but  a  small  part  of  the  net  gains  from  such  crops. 

Shallow-rooted  plants  are  considered  the  most  desirable  for  this 
purpose.  Squash,  melons,  sweet  potatoes,  tomatoes,  and  peanuts  are 
the  most  common  in  California.  The  cultivation  is  done  with  one 
horse  and  a  small  cultivator.  A  clear  space  3  to  4  feet  wide  is  left 
on  each  side  of  the  young  trees.  In  the  Verde  River  Valley  of 
Arizona,  strawberries,  lettuce,  onions,  and  melons  are  raised  in  the 
young  orchards.  In  parts  of  Idaho,  alfalfa  fields  are  frequently 
plowed  under  to  plant  trees.  When  this  is  done,  berries,  beans, 
melons,  onions,  and  tomatoes  can  be  grown  between  the  rows  for 
several  years  without  any  apparent  injury  to  young  trees.  In  north¬ 
ern  Colorado,  raspberries,  gooseberries,  currants,  as  well  as  corn, 
beans,  and  peas  are  often  planted  in  orchards,  while  in  southwestern 
Kansas  it  is  usually  cabbage,  melons,  and  sweet  potatoes. 

In  the  young  apple  orchards  of  Hood  River  Valley,  Oregon,  straw¬ 
berries  are  frequently  planted  between  the  rows.  The  manner  in 
which  this  is  done,  as  well  as  the  system  of  contour  planting  which 
is  there  practiced,  is  shown  in  figure  32.  The  manager  of  a  large 
apple  orchard  company  in  Montana  states  that  no  appreciable  effect 
is  noticed  on  apple  trees  as  a  result  of  growing  potatoes,  cabbage, 
beans,  onions,  and  other  vegetables  between  the  trees  providing  the 
intercrops  are  well  cultivated  and  irrigated.  In  the  fruit  districts 
of  Washington,  intercropping  is  a  common  practice.  In  1907  a  fruit 
grower  raised  on  10  acres  of  two-year-old  trees  cantaloups,  tomatoes, 
peppers,  cucumbers,  corn,  radishes,  beans,  peas,  potatoes,  and  turnips, 
all  of  which  netted  him  $2,086.50,  or  an  average  of  $208.65  an  acre. 

While  opinions  differ  regarding  the  wisdom  of  growing  such  crops 
as  have  been  named  between  the  tree  rows,  most  fruit  growers  are 
404 


IRRIGATION  OF  ORCHARDS. 


35 


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convinced  of  the  beneficial  effects  of  cover  crops.  Notwithstanding 
the  scarcity  and  high  value  of  water  in  the  Riverside  citrus  district, 
the  superintendent  of  a  large  fruit  company  has  for  years  grown  peas 
and  vetch  in  the  orange  and  lemon  orchards  under  his  management 
and  advocates  the  free  use  of  irrigation  water  to  supplement  the 
winter  rains  for  the  rapid  and  vigorous  growth  of  such  crops.  In 
the  walnut  groves  of  Orange  County,  Cal.,  bur  clover  is  sown  in  the 
fall,  given  one  or  two  irrigations  during  the  winter  if  the  rainfall  is 
below  the  normal,  and  plowed  under  in  April. 

The  cost  of  such  cover  crops  as  peas,  vetch,  or  clover  includes  the 
seed,  the  labor  of  sowing  it,  the  water,  and  the  time  required  to  apply 


Fig.  32. — Orchard  showing  strawberries  between  rows  of  trees. 


it.  These  items,  according  to  Dr.  S.  S.  Twombly,  of  Fullerton,  Cal., 
amount  to  from  $2.50  to  $3.25  per  acre.  Twenty  tons  per  acre  of 
green  material  is  perhaps  an  average  crop.  In  this  tonnage  there 
would  be  about  100  pounds  of  nitrogen,  which  at  20  cents  per  pound 
represents  a  value  of  $32  per  acre  for  a  cover  crop  like  vetch. 

Other  beneficial  effects  of  cover  crops  are  quite  fully  summarized 
by  Prof.  W.  S.  Thornber,  horticulturist  of  the  Washington  Agricul¬ 
tural  Experiment  Station.® 


Washington  Sta.  Top.  Bui.  S. 


404 


36 


IRRIGATION  OF  ORCHARDS. 


WINTER  IRRIGATION  OF  ORCHARDS. 


When  water  is  used  outside  of  the  regular  irrigation  period  or, 
what  is  in  many  cases  equivalent,  outside  of  the  growing  season,  it  is 
termed  winter  irrigation.  Over  a  large  part  of  the  arid  region  the 
growing  season  is  limited  by  low  temperatures  to  150  days,  or  less, 
and  when  the  flow  of  streams  is  utilized  only  during  this  period  much 
valuable  water  runs  to  wTaste. 

It  was  for  the  purpose  of  utilizing  some  of  this  waste  that  the 
orchardists  of  the  Pacific  coast  States  and  Arizona  began  the  practice 
of  winter  irrigation.  The  precipitation  usually  occurs  in  winter  in 
the  form  of  rain,  and  large  quantities  of  creek  water  are  then  avail¬ 
able.  This  water  is  spread  over  the  orchards  in  January,  February, 
and  March,  when  deciduous  trees  are  dormant.  The  most  favorable 
conditions  for  this  practice  are  a  mild  winter  climate;  a  deep,  reten¬ 
tive  soil  which  will  hold  the  greater  part  of  the  water  applied ;  deep- 
rooted  trees ;  and  a  soil  moist  from  frequent  rains. 

The  creek  water  which  was  applied  to  some  of  the  prune  orchards 
of  the  Santa  Clara  Valley,  California,  during  the  winter  of  1904.  was 
measured  by  the  agents  of  this  Office  with  the  following  results : 
From  February  27  to  April  23,  1,241  acres  were  irrigated  under  the 
Statler  ditch  to  an  average  depth  of  1.58  feet.  From  February  12  to 
April  23,  2,021  acres  were  irrigated  under  the  Sorosis  and  Calkins 
ditches  to  an  average  depth  of  1.75  feet.  In  the  majority  of  cases  the* 
orchards  which  are  irrigated  in  winter  in  this  valley  receive  no  addi¬ 
tional  supply  of  moisture  other  than  about  1G  inches  of  rain  water. 

In  the  colder  parts  of  the  arid  region  winter  irrigation  is  likewise 
being  practiced  with  satisfactory  results.  The  purpose  is  not  only  to 
store  water  in  the  soil  but  to  prevent  the  winterkilling  of  trees.  Ex¬ 
perience  has  shown  that  it  is  not  best  to  apply  much  water  to  orchards 
during  the  latter  part  of  the  growing  season,  since  it  tends  to  produce 
immature  growth  which  is  easily  damaged  by  frost.  In  many  of  the 
orchards  of  Montana  no  water  is  applied  in  summer  irrigation  after 
August  20.  Owing,  however,  to  the  prevalence  of  warm  chinook 
winds,  which  not  only  melt  the  snow  in  a  night,  but  rob  the  exposed 
soil  of  much  of  its  moisture,  one  or  two  irrigations  are  frequently  nec- 
essarv  in  midwinter. 


[A  list  giving  the  titles  of  all  Farmers’  Bulletins  available  for  distribution 
will  be  sent  free  upon  application  to  any  Member  of  Congress  or  the  Secretary 
of  Agriculture.] 

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